OBJECTIVES: Interferon is one of a large number of soluble mediators of cellular immunity (lymphokines) produced by lymphocytes as a result of immune recognition phenomena. It seems likely that it must have some function in the immune system, possibly as a regulator of immune recognition mechanisms. This proposal is to study the role of interferon in immune phenomena. Specifically, this proposal is to study possible effects of interferon on: a) production and action of other lymphokines, especially mitogenic factor, lymhotoxin, and DNA synthesis inhibitor, all of which seem to play a modulating role in lymphocyte proliferation; b) proliferation of lymphocytes, non-stimulated and those stimulated by specific and non-specific mitogens: c) initiation, maturation, proliferation and function of "killer" cells; d) replication of viruses in lymphocytes, both normal and specifically immune, and also stimulated by non-specific mitogens; and especially in conjunction with other lymphokines, and including an analysis of the consequence of virus replication upon lymphocyte function; e) replication of viruses in macrophages and on macrophage function in processing antigens for presentation to lymphocytes. BIBLIOGRAPHIC REFERENCES: Dion, L. D., Blalock, J. E. and Gifford, G. E., Vitamin A Induced Density-Dependent Inhibition of L-Cell Proliferation. J. Nat. Canc. Instit., 58:795-891, 1977. Dion, L. D., Blalock, J. E and Gifford, G. E., Vitamin A Induced Inhibition of L929 Cell Colong Formation is Specific for Retinoic Acid. Bact. Proc., in press, 1977.